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My EC2 tuning experience has been similar to yours.
I found that mine did not seem to work as Tracy describes in the EC2 manual.
Initially my engine never ran in the region where the MCT is RPM driven. My MCT
pointer was always MAP driven. I beleive at least in my case that a variety of
small issues combined led to this behavior. As i have continued to tweak and
refine my installation I find that it operates more like intended.
Initially all of my tuning was done based on RPM,
MAP, O2, and EGTs. When I designed and built my instrument panel Tracy's EM
didnt exist so I dont have one. Tuning it as I did resulted in acceptable engine
performance, but I knew it could be better. I installed one of Ed Anderson's
EFISM so I could get a look at what was loaded in the MCT. Even though the
engine was running OK, I found many instances of large transitions between
adjacent locations in the table. Using the EFISM I tweaked the MCT and
smoothed all of these transitions. After this I found that the engine would idle
more smoothly and at lower RPMs and I was now running in the region where RPM
drives the MCT.
Another thing I found was the EC2 seems
to be sensitive to location of the MAP vacuum sources in the intake
manifold. My intake uses an essentially stock Mazda lower casting. There are
existing vacuum ports in this casting that I used to plumb the MAP sensors. In
my early debugging efforts Tracy suggested moving these taps out toward the
plenum. I tried this but there was no noticeable difference so I changed it
back.
At the advice of a number of users I added some
small reservoirs, essentially a vacuum capacitor, to smooth the MAP inputs. This
did result in a slight improvement in performance.
After all of the MCT tweaking using the EFISM I
decided to once again try tapping vacuum at the plenum. This time I did notice a
difference with a further improvement at idle settings (smoother and lower RPM).
I believe the less than ideal MCT tune that I started with was masking the
effect of an improved vacuum source. After the tuning and the relocation of
vacuum taps out to the plenum I was able to eliminate the vacuum
reservoirs.
All of this minor tweaking has resulted in major
improvements in engine performance. In my case I dont think it would have been
possible to tweak the engine to this state of tune without the EFISM (or an EM).
I think some sort of tuning aid that provides a visual reference of what the MCT
looks like and what MCT value is being used at any given time is essential.
Being able to snag the data and review it after the fact like Steve has done
would also be incredibly useful.
Mike Wills
RV-4 N144MW
----- Original Message -----
Sent: Wednesday, April 22, 2009 8:13
AM
Subject: [FlyRotary] Re: EC2 address
range issue
Attached is plot of
data collected from my EC2 during a throttle up-throttle down sequence that I
sent to Tracy in mid March. The color bars at the bottom show where the
actual and expected (from the operators manual) table addresses for the
conditions at that time in the run aren’t consistent. The mismatch in
the color bars at the lower RPM and MP show areas that I questioned.
Higher MP than 23” are not accessible to me at this elevation since my engine
is normally aspirated, but the higher MP regions seem to behave as described
in the manual.
As unkind as it is, I
am glad to see that I am not the only one seeing this behavior. I’m
inclined to stop tearing up my installation trying to find a problem that
doesn’t exist. Apparently the EC2 is just doing things we didn’t
expect.
Steve
Boese
RV6A, 13B NA, EC2,
RD1A
-----Original
Message-----
From: Rotary
motors in aircraft [mailto:flyrotary@lancaironline.net] On Behalf Of Bobby J. Hughes
Sent: Wednesday, April 22, 2009 9:01
AM
To: Rotary motors in
aircraft
Subject: [FlyRotary]
Re: EC2 address range issue
I did
hear from Tracy and he agrees I should not be seeing address 37 under this
condition. Will work on it again next week after SNF.
Bobby
From: Rotary
motors in aircraft [mailto:flyrotary@lancaironline.net] On Behalf Of Mark Steitle
Sent: Wednesday, April 22, 2009 7:46
AM
To: Rotary motors in
aircraft
Subject: [FlyRotary]
Re: EC2 address range issue
You may want to post your message on the
EC-2/EM-2 list also.
On Wed, Apr 22, 2009 at 9:06 AM, Bobby J.
Hughes <bhughes@qnsi.net>
wrote:
Bill,
I tested
moving the rpm / map threshold (mode 7A) from 2500 to 3000,4000,2000 and 1200.
I was still seeing a problem in this address range. Not sure it was the same
exact problem but same symptoms. Tune it richer one time and then next time it
need to be leaned. With the MAP at 12.5 and RPM at 2270 I would expect to
using address 26 or 27 not 37. Address range 32-63 are for above 13" MAP and
rpm between 2500 and 3800. 12.5" and 2270 rpm does not meet that condition.
But it is above 10" MAP. Is that a third condition?
I had
the same experience as you reported with mixture address gaps when tuning. I
skip from about 42 to 72 when slowly advancing the throttle one address at a
time. Advance the throttle quickly and the engine would miss and cough. I set
the skipped address range back to near 0 and can advance the throttle
quickly with little hesitation. I think it will need to be fine tuned in
flight.
From: Rotary
motors in aircraft [mailto:flyrotary@lancaironline.net] On Behalf Of Bill Schertz
Sent: Tuesday, April 21, 2009 8:40 PM
To: Rotary motors in
aircraft
Subject:
[FlyRotary] Re: EC2 address range issue
On my EC-2, the map table changes
from low table to high table at 2400 rpm. I don't have a super charger, and my
EC-2 may not be the same model as yours, as Tracy keeps making
changes/improvements.
You are seeing one reading at 3010
rpm and another at 2270, these span the area where mine (according to manual)
switches between low and high map tables.
Bill Schertz
KIS Cruiser
#4045
N343BS
----- Original Message -----
Sent:
Tuesday, April 21, 2009 8:20 PM
Subject:
[FlyRotary] EC2 address range issue
I sent an email to Tracy but
he's at SNF this week and not sure he will see it until next week.
Though I would run this by the group.
Mixture Correction Table address
32-41 are giving me problems. Here is an example of what I am
seeing.
Address 37 , MAP 12.1, RPM
3010, Val +26, O2- 14.5 Tuned perfect. Move the throttle up and down
the map table and engine starts to run poor in the address range. Adjust
throttle back to Address 37 and things have changed.
Address 37, MAP 12.5, RPM
2270, VAL +26, O2- 12.5 Tuned rich.
I have tuned this range a dozen
or more times. It also happens to be right in my taxi range.
Prop in fixed mode at high rpm
setting.
Supercharger 1" bypass
open so no air is being compressed in
manifold.
Prop and supercharger settings
do not seem to make any difference with this
problem.
I played around with mode 7A
changing the rpm vs manifold reference points but did not seem to make a
difference.
I can idle at 10" MAP and 1200
rpm.
(last item before
flight)
--
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